Wireless amplifier



Apr. 3, 1923. 1,450,275

C. T. ALLCUTT WIRELESS AMPLIFIER Filed Dec. 5l, 1918 WITNESSES: INVENTOR PATENT 'errno-a.A

CHESTER T. ALLCUTT, 0E PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING.

HOUSE ELECTRIC VANIA.

MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- WIRELESS AMPLIFIER.

Application led December 31, 1918. erial No. 269,130.

To all whom t may Vcome/r11,

Be it known that I, CHESTER T. ALLoUr'r, a citizen .of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Wireless lAmplifiers, of which the followin is a specification.

fy invention relates to vacuum apparatus of thev type commonly employed for the amplification of impulses in the transmission of intelligence, having particular reference to that type of apparatus wherein the iiow of charged bodies from a hot electrode to a cold electrode is under the control of a grid electrode charged in accordance with the incoming impulses, the

'charged bodies being permitted to traverse said grid electrode to a greater or less degree, dependent upon the potential thereof.

.My invention hasforits object to provide apparatus of the character designated that shall be simple and reliable in operation and more sensitive than the forms of apparatus commonly employed hitherto'for this purpose.

Fig. 1 of the accompanying drawing is a partially sectional perspective view of a vacuum-tube, together with its associated circuits and apparatus illustrating a preferred form of my invention; and Fig. 2 is a partially sectional side view of the apparatus shown in Fig. 1.

Amplifiers are well known wherein a continuous electron stream is emitted from a. hot cathode within an evacuated space, and the number of electrons permitted to impinge upon the anode or cold-electrode is determined byv an intervening grid member connected to the antenna of the line wire so as to be energized in accordance with the incoming impulses. With 'apparatus of this type, as usually constructed in the past, the electronsl left the hot cathode and traveled at high velocity through the grid to the cold plate. Because of this high velocity, ithas been necessary for the grid to acquire a pronounced change in potential and electrostatic iniuence'ffbefore being enabled to appreciably change the number of electrons reaching the cold plate.

In accordance with my invention, I provide means whereby the electrons are emitted from the hot cathode and are then brought down to a relatively low velocity before being acted upon b the grid, thus permitting the grid to pro uce a much more vmarked change in thenumber of electrons passing,

witi a given change in the potential of the gri i Referring to the drawing for a more detailed understanding of my invention, I show an evacuated container at l in which are mounted twoplate electrodes 2 and 3, a hot-wire cathode 4, and a grid electrode 5. 'I he hot cathode 4 preferably liessubstantlally in the plane of the electrode 3, as shown, and the electrode 2 is, parallel to the common plane of the electrodes 3 and 4 and spaced some distance therefrom, The grid 5 tnounted between the plate electrodes 2 an A magnet 6 is disposed outside the contamer in such manner as to produce a magnetic field, the lines of which are substantially parallel to the plate electrodes 2 and 3 or transverse to an electron path between these electrodes. l

The electrodes 2 and 4 are connected, respectively, t0 the positive and negative terminals of a battery 7 so as to maintain a fixed unidirectional dierence of potential therebetween, and the electrode 4 is further connected across a small current source in orderto'maintain this electrode at incandescence. Areceiving device 8, such, for example,

as a telephone receiver only, is connected between the electrodes 3 and 4 but any other well known form of receiver on receiver circuit can be employed. rThe receiving circuit from an -antenna 9 is connected between the electrodes 3 and 5.

Having thus described the arrangement of a system embodying my invention, the operation thereof is as follows: Upon heating the electrode 4 by the passage of electric current therethrough, a stream of electrons is generated and4 flows towards the plate 2 because of. the difference of potential between the electrodes 2 and 4. The effect of .the magnetic field produced by the magnet .6, however, is to lcause theV path of the electrons to bend varound in eycloidal shape to such an extentfthat the electrons are forced to travel away from the plate 2, as indicated by the dotted lines. The electrostatic attraction Aof the plate 2 upon the electrons moving therefrom tends to radically lower the velocity of the electrons so` that,. when they reach the grid 6, they are moving at a relatively low velocity, passing through the grid 5 and impinging upon the electrode plate 3 to produce current iiow through the receiv- 311g device 8. The edect of the incoming impulses of the antenna 9 is to continuously nier ai@ perenni of the grid 5, and Slight alterations in the potential thereof produce pronounced changes in the number of relatively low-velocity electrons attempting to pass therethrough, thus causing the receivmg aPPaflUS t0 be extremely sensitive to changes in the grid potential.

The electrostatic iniiuence of the electrode 2 is unaii'ected by whether this electrode within or without the tube My invention is illustrated in coimttil with a wireless system wherein it may iurther be employed for generating and amplitying but l equally contemplate its use in connection with line-wire systems, as ior a telephone ampiiiier.

While have shown my invention in its preferred form, it will be obvious to those skilled in the art that it is susceptible of va.- rious minor changes and modiiications without departing from the spirit thereof and l' desire, thei'eiore, that onlysuch limitations shall be placed thereupon as are imposed by the prior art or are speciiically set forth in the appended claims.

i claim as my invention:

i. ln a vacuum-type amplifier, a hot cath-,

ode Jfor the production of a stream of electrons, an auxiliary anode disposed adjacent thereto, means for maintaining a difference of potential between said electrodes, whereby substantially all the electrons emitted by said cathode are drawn toward said anode, means producing a magnetic field transverse to the path of said electrons, whereby they are forced to assume a cycloidal path and eventually travel away from said anode. with attendant diminution of velocity, a grid electrode disposed to intercept the electron path at this point of relatively low ve- 'locity, a main anode, disposed beyond said grid, means responsive to variations in current flow between said cathode and said main anode, and means for varying the potential of said grid electrode.

2. A method of increasing the efiiciency of vacuum-tube amplifiers comprising the step of initiating the movement of an electronic stream in a given direction and then causing the same electronic stream to move in substantially the opposite direction.

3. lin combination with means for producing electronic emission in a given direction, of means for causing such emission to move in substantially the opposite direction.

4. In combination with means for producfu-,v ing electronic emission, a plate co-operative Leaders normal thereto and still further meanstor giving to said electrons a velocity component toward said pate.

5. In combination with means for producing a stream of electried bodies, a plate cooperating with said means 'for taking up the charges ot said electrified bodies, means for giving to said charged bodies a velocity away from said piate in a direction substanially normal thereto, and further means 'for thereafter giving to said bodies a veloctoward said plate.

6. i method of increasing the eciency ci vacuum-tube amplifiers comprising the step oi' giving to the emission an accelerating gradient in the direction of the current iiow toward the receiving plate and then reversing the gradient in the direction oi' such current fiow to such a degree that in the neighborhood of a grid in the path of such emission stream the velocity shall be `-substantially that of the original stream.

7. ln combination with 'he filament, grid, and plate oi' a vacuum-tube ampliiier, means for increasing the velocity ot the stream ow of electrons away from the grid and plate in a direction substantially normal thereto, and further means for diminishing such velocityT and directing the stream iiow toward the grid and plate.

8. ln combination with 'the cathode of a vacuum-tube amplifier, an electrode opposite said cathode, a second electrode in a plane substantially parallel to said cathode, and a grid between said two electrodes.

9. ln combination with the filament and plate of a vacuum-tube amplifier, means for increasing the velocity of the stream liow of electrons away from the plate, further means for diminishing such velocity and directing the stream iiow toward the plate, and still further means for controlling the electron dow between said iilament and plate.

10. in combination with the filament, grid, and plate of a vacuum-tube ampliiier, means for increasing the velocity oi the stream,

flow of electrons away from the grid and plate, Jrurther means for diminishing such velocity and directing the stream flow toward the grid and plate, and still further means for setting up a magnetic field substantially parallel to the planes of said electrodes.

In i testimony whereof, I have hereunto subscribed my naine this 12th day of Dec.

CHESTER T. ALLCUTT. 

